The Atypical Dual Specificity Phosphatase DUSP15 Regulates Jak1-Mediated STAT3 Activation.

The signal transducer and activator of transcription 3 (STAT3) protein is a key regulator of cell differentiation, proliferation, and survival in hematopoiesis, immune responses, and other biological systems. STAT3 transcriptional activity is strictly regulated through various mechanisms, such as phosphorylation and dephosphorylation. In this study, we attempted to identify novel phosphatases which regulate STAT3 activity in response to cytokine stimulations. To this end, leukemia inhibitory factor (LIF)/STAT3 dependent phosphatase induction was evaluated in the mouse hepatoma cell line Hepa1-6. After LIF stimulation, the expression of several atypical dual specific phosphatases (aDUSPs) was upregulated in Hepa1-6 cells. Among the LIF-induced aDUSPs, we focused on DUSP15 and clarified its functions in LIF/STAT3 signaling using RNA interference. DUSP15 knockdown decreased LIF-induced Socs3 mRNA expression and STAT3 translocation. Furthermore, loss of DUSP15 reduced the phosphorylation of STAT3 at Tyr705 and Janus family tyrosine kinase 1 (Jak1) at Tyr1034/1035 in response to LIF. The interaction between Jak1 and DUSP15 was observed in LIF-stimulated Hepa1-6 cells. We also demonstrated the suppression of granulocyte colony-stimulating factor (G-CSF)-mediated gp130/STAT3-dependent cell growth of Ba/F-G133 cells via DUSP15 knockdown. Therefore, DUSP15 functions as a positive feedback regulator in the Jak1/STAT3 signaling cascade.

Inhibition of miR-194-5p avoids DUSP9 downregulation thus limiting sepsis-induced cardiomyopathy.

Sepsis-induced cardiomyopathy (SIC) is described as a reversible myocardial depression that occurs in patients with septic shock. Increasing evidence shows that microRNA-194-5p (miR-194-5p) participates in the regulation of oxidative stress, mitochondrial dysfunction, and apoptosis and its expression is associated with the occurrence and progression of cardiovascular disease; however, the effects of miR-194-5p in SIC are still unclear. This study explores whether miR-194-5p could modulate SIC by affecting oxidative stress, mitochondrial function, and apoptosis. Experimental septic mice were induced by intraperitoneal injection of lipopolysaccharide (LPS) in C57BL/6J mice. The biological role of miR-194-5p in SIC in vivo was investigated using cardiac echocardiography, ELISA, western blot, qRT-PCR, transmission electron microscopy, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, bioinformatics analysis, and dual-luciferase reporter gene assay. Our major finding is that miR-194-5p antagomir mitigates sepsis-induced cardiac dysfunction, inflammation, oxidative stress, apoptosis and mitochondrial dysfunction in the hearts of septic mice, while miR-194-5p agomir triggers the opposite effects. Furthermore, dual-specificity phosphatase 9 (DUSP9) is a direct target of miR-194-5p and the cardioprotective effects of miR-194-5p antagomir on cardiac dysfunction, inflammation, apoptosis, mitochondrial dysfunction and oxidative stress are abolished through inhibiting DUSP9. Therefore, miR-194-5p inhibition could mitigate SIC via DUSP9 in vivo and the novel miR-194-5p/DUSP9 axis might be the potential treatment targets for SIC patients.

m6A-mediated HDAC9 upregulation promotes particulate matter-induced airway inflammation via epigenetic control of DUSP9-MAPK axis and acts as an inhaled nanotherapeutic target.

Exposure to particulate matter (PM) can cause airway inflammation and worsen various airway diseases. However, the underlying molecular mechanism by which PM triggers airway inflammation has not been completely elucidated, and effective interventions are lacking. Our study revealed that PM exposure increased the expression of histone deacetylase 9 (HDAC9) in human bronchial epithelial cells and mouse airway epithelium through the METTL3/m6A methylation/IGF2BP3 pathway. Functional assays showed that HDAC9 upregulation promoted PM-induced airway inflammation and activation of MAPK signaling pathway in vitro and in vivo. Mechanistically, HDAC9 modulated the deacetylation of histone 4 acetylation at K12 (H4K12) in the promoter region of dual specificity phosphatase 9 (DUSP9) to repress the expression of DUSP9 and resulting in the activation of MAPK signaling pathway, thereby promoting PM-induced airway inflammation. Additionally, HDAC9 bound to MEF2A to weaken its anti-inflammatory effect on PM-induced airway inflammation. Then, we developed a novel inhaled lipid nanoparticle system for delivering HDAC9 siRNA to the airway, offering an effective treatment for PM-induced airway inflammation. Collectively, we elucidated the crucial regulatory mechanism of HDAC9 in PM-induced airway inflammation and introduced an inhaled therapeutic approach targeting HDAC9. These findings contribute to alleviating the burden of various airway diseases caused by PM exposure.

Dual-specificity phosphatases 13 and 27 as key switches in muscle stem cell transition from proliferation to differentiation.

Muscle regeneration depends on muscle stem cell (MuSC) activity. Myogenic regulatory factors, including myoblast determination protein 1 (MyoD), regulate the fate transition of MuSCs. However, the direct target of MYOD in the process is not completely clear. Using previously established MyoD knock-in (MyoD-KI) mice, we revealed that MyoD targets dual-specificity phosphatase (Dusp) 13 and Dusp27. In Dusp13:Dusp27 double knock-out mice, the ability for muscle regeneration after injury was reduced. Moreover, single-cell RNA sequencing of MyoD-high expressing MuSCs from MyoD-KI mice revealed that Dusp13 and Dusp27 are expressed only in specific populations within MyoD-high MuSCs, which also express Myogenin. Overexpressing Dusp13 in MuSCs causes premature muscle differentiation. Thus, we propose a model where DUSP13 and DUSP27 contribute to the fate transition of MuSCs from proliferation to differentiation during myogenesis.

Atypical phosphatase DUSP11 inhibition promotes nc886 expression and potentiates gemcitabine-mediated cell death through NF-kB modulation.

Pancreatic ductal adenocarcinoma (PDAC) represents one of the deadliest cancers among all solid tumors. First-line treatment relies on gemcitabine (Gem) and despite treatment improvements, refractoriness remains a universal challenge. Attempts to decipher how feedback-loops control signaling pathways towards drug resistance have gained attention in recent years, particularly focused on the role of phosphatases. In this study, a CRISPR/Cas9-based phenotypic screen was performed to identify members from the dual-specificity phosphatases (DUSP) family potentially acting on Gem response in PDAC cells. The approach revealed the atypical RNA phosphatase DUSP11 as a potential target, whose inhibition creates vulnerability of PDAC cells to Gem. DUSP11 genetic inhibition impaired cell survival and promoted apoptosis, synergistically enhancing Gem cytotoxicity. In silico transcriptome analysis of RNA-seq data from PDAC human samples identified NF-ĸB signaling pathway highly correlated with DUSP11 upregulation. Consistently, Gem-induced NF-ĸB phosphorylation was blocked upon DUSP11 inhibition in vitro. Mechanistically, we found that DUSP11 directly impacts nc886 expression and modulates PKR-NF-ĸB signaling cascade after Gem exposure in PDAC cells resulting in resistance to Gem-induced cell death. In conclusion, this study provides new insights on DUSP11 role in RNA biology and Gem response in PDAC cells.

Inhibiting TRIM8 alleviates adipocyte inflammation and insulin resistance by regulating the DUSP14/MAPKs pathway.

Obesity is a low-grade chronic inflammation induced by the pathological expansion of adipocytes which allows the development of obesity-associated metabolic diseases like type 2 diabetes mellitus (T2D) and non-alcoholic fatty liver disease (NAFLD). However, mechanisms regulating adipocyte inflammation remain poorly understood. Here, we observed that TRIM8 was upregulated in adipocyte inflammation and insulin resistance while DUSP14 was downregulated. TRIM8 deficiency and DUSP14 over-expression decreased the level of inflammatory cytokines, increased glucose uptake content, and improved insulin signalling transduction compared to LPS treatment alone. Conversely, silencing DUSP14 increased the expression of inflammatory cytokines. It decreased the glucose uptake content and the phosphorylation level of proteins involved in insulin signalling, further impairing insulin signalling and aggravating insulin resistance. Furthermore, The decreased level of inflammatory cytokines, increased glucose uptake, and improved insulin signalling transduction caused by TRIM8 deficiency were reversed by down-regulated DUSP14. Collectively, our findings revealed that TRIM8 can regulate adipocyte inflammation and insulin resistance by regulating the MAPKs pathway which is dependent on DUSP14.

Inhibition of DUSP18 impairs cholesterol biosynthesis and promotes anti-tumor immunity in colorectal cancer.

Tumor cells reprogram their metabolism to produce specialized metabolites that both fuel their own growth and license tumor immune evasion. However, the relationships between these functions remain poorly understood. Here, we report CRISPR screens in a mouse model of colo-rectal cancer (CRC) that implicates the dual specificity phosphatase 18 (DUSP18) in the establishment of tumor-directed immune evasion. Dusp18 inhibition reduces CRC growth rates, which correlate with high levels of CD8+ T cell activation. Mechanistically, DUSP18 dephosphorylates and stabilizes the USF1 bHLH-ZIP transcription factor. In turn, USF1 induces the SREBF2 gene, which allows cells to accumulate the cholesterol biosynthesis intermediate lanosterol and release it into the tumor microenvironment (TME). There, lanosterol uptake by CD8+ T cells suppresses the mevalonate pathway and reduces KRAS protein prenylation and function, which in turn inhibits their activation and establishes a molecular basis for tumor cell immune escape. Finally, the combination of an anti-PD-1 antibody and Lumacaftor, an FDA-approved small molecule inhibitor of DUSP18, inhibits CRC growth in mice and synergistically enhances anti-tumor immunity. Collectively, our findings support the idea that a combination of immune checkpoint and metabolic blockade represents a rationally-designed, mechanistically-based and potential therapy for CRC.

ASAH1 facilitates TNBC by DUSP5 suppression-driven activation of MAP kinase pathway and represents a therapeutic vulnerability.

Triple-negative breast cancer (TNBC) is a subtype of breast cancer that is prone to metastasis and therapy resistance. Owing to its aggressive nature and limited availability of targeted therapies, TNBC is associated with higher mortality as compared to other forms of breast cancer. In order to develop new therapeutic options for TNBC, we characterized the factors involved in TNBC growth and progression. Here, we demonstrate that N-acylsphingosine amidohydrolase 1 (ASAH1) is overexpressed in TNBC cells and is regulated via p53 and PI3K-AKT signaling pathways. Genetic knockdown or pharmacological inhibition of ASAH1 suppresses TNBC growth and progression. Mechanistically, ASAH1 inhibition stimulates dual-specificity phosphatase 5 (DUSP5) expression, suppressing the mitogen-activated protein kinase (MAPK) pathway. Furthermore, pharmacological cotargeting of the ASAH1 and MAPK pathways inhibits TNBC growth. Collectively, we unmasked a novel role of ASAH1 in driving TNBC and identified dual targeting of the ASAH1 and MAPK pathways as a potential new therapeutic approach for TNBC treatment.

Exosomal miR-1228-5p down-regulates DUSP22 to promotes cell proliferation and migration in small cell lung cancer.

BACKGROUND: Exosomes play a crucial role in promoting tumor progression, dissemination, and resistance to treatment. These extracellular vesicles hold promise as valuable indicators for cancer detection. Our investigation focuses on exploring the significance and clinical relevance of exosomal miRNAs in small cell lung cancer (SCLC). METHODS: Serum exosomes were isolated from both SCLC patients and healthy controls, and subjected to exosomal miRNA sequencing analysis. Mimics and inhibitors were employed to investigate the function of exosomal miR-1128-5p in cell migration and proliferation, both in vitro and in vivo. Western blot and luciferase assay were utilized to identify the interaction between miR-1228-5p and dual specificity phosphatase 22 (DUSP22). RESULTS: Exosomal miRNA sequencing analysis revealed enrichment of specific miRNAs in SCLC compared to healthy controls. Circulating miR-1228-5p was upregulated in SCLC patients, associated with advanced stages, suggesting its potential oncogenic role. In vitro, miR-1228-5p expression was significantly higher in SCLC cells than in normal cells. SCLC cell-derived exosomes contained elevated levels of miR-1228-5p, facilitating its entry into co-cultured cells. Notably, migration and proliferation induced by SCLC exosomes were mainly mediated by miR-1228-5p. In vivo experiments confirmed these findings. Western blot analysis demonstrated miR-1228-5p's regulation of DUSP22 expression, and luciferase reporter assay validated DUSP22 as a direct target gene. Overexpressing DUSP22 counteracted miR-1228-5p's promotion of SCLC cell proliferation and migration. CONCLUSIONS: Collectively, our results suggest that exosomes play a role in facilitating cancer growth and metastasis by delivering miR-1228-5p. Moreover, circulating exosomal miR-1228-5p may serve as a potential marker for SCLC diagnosis and prognosis.

Nepetoidin B Alleviates Liver Ischemia/Reperfusion Injury via Regulating MKP5 and JNK/P38 Pathway.

Background: Nepetoidin B (NB) has been reported to possess anti-inflammatory, antibacterial, and antioxidant properties. However, its effects on liver ischemia/reperfusion (I/R) injury remain unclear. Methods: In this study, a mouse liver I/R injury model and a mouse AML12 cell hypoxia reoxygenation (H/R) injury model were used to investigate the potential role of NB. Serum transaminase levels, liver necrotic area, cell viability, oxidative stress, inflammatory response, and apoptosis were evaluated to assess the effects of NB on liver I/R and cell H/R injury. Quantitative polymerase chain reaction (qPCR) and Western blotting were used to measure mRNA and protein expression levels, respectively. Molecular docking was used to predict the binding capacity of NB and mitogen-activated protein kinase phosphatase 5 (MKP5). Results: The results showed that NB significantly reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, liver necrosis, oxidative stress, reactive oxygen species (ROS) content, inflammatory cytokine content and expression, inflammatory cell infiltration, and apoptosis after liver I/R and AML12 cells H/R injury. Additionally, NB inhibited the JUN protein amino-terminal kinase (JNK)/P38 pathway. Molecular docking results showed good binding between NB and MKP5 proteins, and Western blotting results showed that NB increased the protein expression of MKP5. MKP5 knockout (KO) significantly diminished the protective effects of NB against liver injury and its inhibitory effects on the JNK/P38 pathway. Conclusion: NB exerts hepatoprotective effects against liver I/R injury by regulating the MKP5-mediated P38/JNK signaling pathway.

Dual-Specificity Phosphatase 4 Promotes Malignant Features in Colorectal Cancer Through Cyclic-AMP Response Element Binding Protein/Protein Kinase CAMP-Activated Catalytic Subunit Beta Activation.

INTRODUCTION: Previous studies have demonstrated that Dual-specificity phosphatase 4 (DUSP4) plays an important role in the progression of different tumor types. However, the role and mechanism of DUSP4 in colorectal cancer (CRC) remain unclear. AIMS: We investigate the role and mechanisms of DUSP4 in CRC. METHODS: Immunohistochemistry was used to investigate DUSP4 expression in CRC tissues. Cell proliferation, apoptosis and migration assays were used to validate DUSP4 function in vitro and in vivo. RNA-sequence assay was used to identify the target genes of DUSP4. Human phosphokinase array and inhibitor assays were used to explore the downstream signaling of DUSP4. RESULTS: DUSP4 expression was upregulated in CRC tissues relative to normal colorectal tissues, and DUSP4 expression showed a significant positive correlation with CRC stage. Consistently, we found that DUSP4 was highly expressed in colorectal cancer cells compared to normal cells. DUSP4 knockdown inhibits CRC cell proliferation, migration and promotes apoptosis. Furthermore, the ectopic expression of DUSP4 enhanced CRC cell proliferation, migration and diminished apoptosis in vitro and in vivo. Human phosphokinase array data showed that ectopic expression of DUSP4 promotes CREB activation. RNA-sequencing data showed that PRKACB acts as a downstream target gene of DUSP4/CREB and enhances CREB activation through PKA/cAMP signaling. In addition, xenograft model results demonstrated that DUSP4 promotes colorectal tumor progression via PRKACB/CREB activation in vivo. CONCLUSION: These findings suggest that DUSP4 promotes CRC progression. Therefore, it may be a promising therapeutic target for CRC.

MicroRNA-671-5p regulates the inflammatory response of periodontal ligament stem cells via the DUSP8/p38 MAPK pathway.

BACKGROUND: MicroRNAs are differentially expressed in periodontitis tissues. They are involved in cellular responses to inflammation and can be used as markers for diagnosing periodontitis. Microarray analysis showed that the expression level of microRNA-671-5p in periodontal tissues of patients with periodontitis was increased. In this study, we investigated the mechanism of action of microRNA-671-5p in human periodontal ligament stem cells (hPDLSCs) under inflammatory conditions. METHODS AND RESULTS: HPDLSCs were treated with lipopolysaccharide (LPS) to establish an inflammation model. The cell survival rate was determined using the cell counting kit-8 (CCK8). Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot analyses were used to detect the expression of microRNA-671-5p and dual-specificity phosphatase (DUSP) 8 proteins, respectively, Interleukin (IL)-6, IL-1ß, and tumor necrosis factor (TNF)-α were detected using qRT-PCR and Enzyme-linked immunosorbent assay (ELISA). A dual-luciferase reporter system was employed to determine the relationship between micoRNA-671-5p and DUSP8 expression. Activation of the p38 mitogen-activated protein kinase (MAPK) signaling pathway was confirmed using western blot analysis. Following the treatment of hPDLSCs with LPS, the expression levels of microRNA-671-5p in hPDLSCs were increased, cell viability decreased, and the expression of inflammatory factors displayed an increasing trend. MicroRNA-671-5p targets and binds to DUSP8. Silencing microRNA-671-5p or overexpressing DUSP8 can improve cell survival rate and reduce inflammatory responses. When DUSP8 was overexpressed, the expression of p-p38 was reduced. CONCLUSIONS: microRNA-671-5p targets DUSP8/p38 MAPK pathway to regulate LPS-induced proliferation and inflammation in hPDLSCs.

Epithelial cells derived exosomal miR-203a-3p facilitates stromal inflammation of type IIIA chronic prostatitis/chronic pelvic pain syndrome by targeting DUSP5 and increasing MCP-1 generation.

Increased proinflammatory cytokines and infiltration of inflammatory cells in the stroma are important pathological features of type IIIA chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS-A), and the interaction between stromal cells and other cells in the inflammatory microenvironment is closely related to the inflammatory process of CP/CPPS-A. However, the interaction between stromal and epithelial cells remains unclear. In this study, inflammatory prostate epithelial cells (PECs) released miR-203a-3p-rich exosomes and facilitated prostate stromal cells (PSCs) inflammation by upregulating MCP-1 expression. Mechanistically, DUSP5 was identified as a novel target gene of miR-203a-3p and regulated PSCs inflammation through the ERK1/2/MCP-1 signaling pathway. Meanwhile, the effect of exosomes derived from prostatic fluids of CP/CPPS-A patients was consistent with that of exosomes derived from inflammatory PECs. Importantly, we demonstrated that miR-203a-3p antagomirs-loaded exosomes derived from PECs targeted the prostate and alleviated prostatitis by inhibiting the DUSP5-ERK1/2 pathway. Collectively, our findings provide new insights into underlying the interaction between PECs and PSCs in CP/CPPS-A, providing a promising therapeutic strategy for CP/CPPS-A.

Dual-specificity phosphatase 26 protects against kidney injury caused by ischaemia-reperfusion through restraint of TAK1-JNK/p38-mediated apoptosis and inflammation of renal tubular epithelial cells.

Dual-specificity phosphatase 26 (DUSP26) acts as a pivotal player in the transduction of signalling cascades with its dephosphorylating activity. Currently, DUSP26 attracts extensive attention due to its particular function in several pathological conditions. However, whether DUSP26 plays a role in kidney ischaemia-reperfusion (IR) injury is unknown. Aims of the current work were to explore the relevance of DUSP26 in kidney IR damage. DUSP26 levels were found to be decreased in renal tubular epithelial cells following hypoxia-reoxygenation (HR) and kidney samples subjected to IR treatments. DUSP26-overexpressed renal tubular epithelial cells exhibited protection against HR-caused apoptosis and inflammation, while DUSP26-depleted renal tubular epithelial cells were more sensitive to HR damage. Upregulation of DUSP26 in rat kidneys by infecting adenovirus expressing DUSP26 markedly ameliorated kidney injury caused by IR, while also effectively reducing apoptosis and inflammation. The mechanistic studies showed that the activation of transforming growth factor-ß-activated kinase 1 (TAK1)-JNK/p38 MAPK, contributing to kidney injury under HR or IR conditions, was restrained by increasing DUSP26 expression. Pharmacological restraint of TAK1 markedly diminished DUSP26-depletion-exacebated effects on JNK/p38 activation and HR injury of renal tubular cells. The work reported a renal-protective function of DUSP26, which protects against IR-related kidney damage via the intervention effects on the TAK1-JNK/p38 axis. The findings laid a foundation for understanding the molecular pathogenesis of kidney IR injury and provide a prospective target for treating this condition.

[Knockdown of dual-specificity phosphatase 5 (DUSP5) inhibits BCG-induced inflammatory response in RAW264.7 macrophages via blocking NF-κB signaling pathway].

Objective To explore the regulatory role of dual-specificity phosphatase 5 (DUSP5) in BCG-mediated inflammatory response in mouse RAW264.7 macrophages. Methods Western blot analysis was employed to detect the expression changes of DUSP5 in BCG-infected RAW264.7 macrophages at the period of 0.5, 1, 2, 4, 6, 8, 12 and 24 hours. Intracellular DUSP5 was reduced by small interfering RNA (siRNA) and transfected RAW264.7 macrophages were divided into siRNA-negative control (si-NC) group, DUSP5 knockdown (si-DUSP5) group, si-NC combined BCG infection group, and si-DUSP5 combined BCG infection group. Real-time quantitative PCR was conducted to measure the mRNA expression of interleukin 1ß (IL-1ß), IL-6, tumor necrosis factor α (TNF-α), and IL-10 in cells. ELISA was performed to measure the concentration of the cytokines in cell culture medium. Western blot analysis was performed to detect the expression changes of cellular nuclear factor κB (NF-κB) and phosphorylated NF-κB (p-NF-κB). Results BCG infection upregulated DUSP5 protein expression in RAW264.7 macrophages with the expression of DUSP5 reaching the peak after 4 hours' BCG stimulation. Comparing with si-NC combined BCG infection group, DUSP5 knockdown inhibited the expression and secretion of pro-inflammatory factors IL-1ß, IL-6, and TNF-α, while the expression of the anti-inflammatory factor IL-10 was not affected by DUSP5. Moreover, knockdown of DUSP5 inhibited the phosphorylation of NF-κB in cells. Conclusion DUSP5 knockdown inhibites BCG-mediated macrophage inflammatory response via blocking NF-κB signaling activation.

A Negative Regulatory Feedback Loop within the JAK-STAT Pathway Mediated by the Protein Tyrosine Phosphatase DUSP14 in Shrimp.

The JAK-STAT pathway is a central communication node for various biological processes. Its activation is characterized by phosphorylation and nuclear translocation of the transcription factor STAT. The regulatory balance of JAK-STAT signaling is important for maintenance of immune homeostasis. Protein tyrosine phosphatases (PTPs) induce dephosphorylation of tyrosine residues in intracellular proteins and generally function as negative regulators in cell signaling. However, the roles of PTPs in JAK-STAT signaling, especially in invertebrates, remain largely unknown. Pacific white shrimp Penaeus vannamei is currently an important model for studying invertebrate immunity. This study identified a novel member of the dual-specificity phosphatase (DUSP) subclass of the PTP superfamily in P. vannamei, named PvDUSP14. By interacting with and dephosphorylating STAT, PvDUSP14 inhibits the excessive activation of the JAK-STAT pathway, and silencing of PvDUSP14 significantly enhances humoral and cellular immunity in shrimp. The promoter of PvDUSP14 contains a STAT-binding motif and can be directly activated by STAT, suggesting that PvDUSP14 is a regulatory target gene of the JAK-STAT pathway and mediates a negative feedback regulatory loop. This feedback loop plays a role in maintaining homeostasis of JAK-STAT signaling and is involved in antibacterial and antiviral immune responses in shrimp. Therefore, the current study revealed a novel inhibitory mechanism of JAK-STAT signaling, which is of significance for studying the regulatory mechanisms of immune homeostasis in invertebrates.

DUSP8-attenuated ERK1/2 signaling mediates lipogenesis and steroidogenesis in chicken granulosa cells.

The lipogenesis and steroidogenesis of granulosa cells are crucial during follicular development, yet it remains unclear whether dual-specificity phosphatase 8 (DUSP8) is involved. In this study, the specific role of DUSP8 in lipogenesis and steroidogenesis was investigated through culturing chicken granulosa cells in vitro. The results revealed that the expression levels of adipogenic genes were elevated after DUSP8 overexpression and reduced after knockdown. The same was observed for lipid deposition in granulosa cells. Meanwhile, the steroidogenic gene expression and progesterone synthesis were promoted after DUSP8 overexpression and inhibited after knockdown. In addition, we also found that DUSP8 blocked the phosphorylation of extracellular regulatory kinase 1/2 (ERK1/2). Based on the previous results that activated ERK1/2 signaling inhibited lipid deposition and progesterone synthesis in chicken granulosa cells, we demonstrated that DUSP8 promoted lipid deposition and progesterone synthesis through mediating the ERK1/2 signaling pathway. The results will improve our understanding of the molecular regulatory mechanisms regarding lipid metabolism and progesterone synthesis in chicken granulosa cells.

Increasing expression of dual-specificity phosphatase 12 mitigates oxygen-glucose deprivation/reoxygenation-induced neuronal apoptosis and inflammation through inactivation of the ASK1-JNK/p38 MAPK pathway.

Dual-specificity phosphatase 12 (DUSP12) is abnormally expressed under various pathological conditions and plays a crucial role in the pathological progression of disorders. However, the role of DUSP12 in cerebral ischaemia/reperfusion injury has not yet been investigated. This study explored the possible link between DUSP12 and cerebral ischaemia/reperfusion injury using an oxygen-glucose deprivation/reoxygenation (OGD/R) model. Marked decreases in DUSP12 levels have been observed in cultured neurons exposed to OGD/R. DUSP12-overexpressed neurons were resistant to OGD/R-induced apoptosis and inflammation, whereas DUSP12-deficient neurons were vulnerable to OGD/R-evoked injuries. Further investigation revealed that DUSP12 overexpression or deficiency affects the phosphorylation of apoptosis signal-regulating kinase 1 (ASK1), c-Jun NH2-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) in neurons under OGD/R conditions. Moreover, blockade of ASK1 diminished the regulatory effect of DUSP12 deficiency on JNK and p38 MAPK activation. In addition, DUSP12-deficiency-elicited effects exacerbating neuronal OGD/R injury were reversed by ASK1 blockade. In summary, DUSP12 protects against neuronal OGD/R injury by reducing apoptosis and inflammation through inactivation of the ASK1-JNK/p38 MAPK pathway. These findings imply a neuroprotective function for DUSP12 in cerebral ischaemia/reperfusion injury.

The lincRNA JUNI regulates the stress-dependent induction of c-Jun, cellular migration and survival through the modulation of the DUSP14-JNK axis.

Cancer cells employ adaptive mechanisms to survive various stressors, including genotoxic drugs. Understanding the factors promoting survival is crucial for developing effective treatments. In this study, we unveil a previously unexplored long non-coding RNA, JUNI (JUN-DT, LINC01135), which is upregulated by genotoxic drugs through the activation of stress-activated MAPKs, JNK, and p38 and consequently exerts positive control over the expression of its adjacent gene product c-Jun, a well-known oncoprotein, which transduces signals to multiple transcriptional outputs. JUNI regulates cellular migration and has a crucial role in conferring cellular resistance to chemotherapeutic drugs or UV radiation. Depletion of JUNI markedly increases the sensitivity of cultured cells and spheroids to chemotherapeutic agents. We identified 57 proteins interacting with JUNI. The activity of one of them the MAPK phosphatase and inhibitor, DUSP14, is counteracted by JUNI, thereby, facilitating efficient JNK phosphorylation and c-Jun induction when cells are exposed to UV radiation. The antagonistic interplay with DUSP14 contributes not only to c-Jun induction but also augments the survival of UV-exposed cells. In summary, we introduce JUNI as a novel stress-inducible regulator of c-Jun, positioning it as a potential target for enhancing the sensitivity of cancer cells to chemotherapy.

Impaired malin expression and interaction with partner proteins in Lafora disease.

Lafora disease (LD) is an autosomal recessive myoclonus epilepsy with onset in the teenage years leading to death within a decade of onset. LD is characterized by the overaccumulation of hyperphosphorylated, poorly branched, insoluble, glycogen-like polymers called Lafora bodies. The disease is caused by mutations in either EPM2A, encoding laforin, a dual specificity phosphatase that dephosphorylates glycogen, or EMP2B, encoding malin, an E3-ubiquitin ligase. While glycogen is a widely accepted laforin substrate, substrates for malin have been difficult to identify partly due to the lack of malin antibodies able to detect malin in vivo. Here we describe a mouse model in which the malin gene is modified at the C-terminus to contain the c-myc tag sequence, making an expression of malin-myc readily detectable. Mass spectrometry analyses of immunoprecipitates using c-myc tag antibodies demonstrate that malin interacts with laforin and several glycogen-metabolizing enzymes. To investigate the role of laforin in these interactions we analyzed two additional mouse models: malin-myc/laforin knockout and malin-myc/LaforinCS, where laforin was either absent or the catalytic Cys was genomically mutated to Ser, respectively. The interaction of malin with partner proteins requires laforin but is not dependent on its catalytic activity or the presence of glycogen. Overall, the results demonstrate that laforin and malin form a complex in vivo, which stabilizes malin and enhances interaction with partner proteins to facilitate normal glycogen metabolism. They also provide insights into the development of LD and the rescue of the disease by the catalytically inactive phosphatase.